Electrically Insulating Cage Nut

ABSTRACT

An electrically insulating cage nut ( 10 ) having a nut body ( 12 ) which is held in a cage ( 14 ), in which the nut body ( 12 ) has a cylindrical attachment ( 16 ) and a broadened holding element ( 18 ), and the cylindrical attachment ( 16 ) has an internal thread ( 20 ) and extends through an opening ( 22 ) in the cage ( 14 ) to the outside, wherein the internal diameter of the opening ( 22 ) is substantially larger than the external diameter of the cylindrical attachment ( 16 ), but is smaller than the external size of the holding element ( 18 ), and an insulator apparatus ( 24 ) is arranged between the cage ( 14 ) and cylindrical attachment ( 16 ), wherein the insulator apparatus ( 24 ) is formed integrally, and in consequence the cage nut ( 10 ) consists of only three components ( 12, 14, 24 ).

TECHNICAL FIELD

The present invention relates to an electrically insulating cage nutcomprising a nut body which is contained in a cage, in which the nutbody comprises a cylindrical projection and a widened holding element,and the cylindrical projection has an internal thread and extendsoutwards through an opening in the cage, the internal diameter of theopening being considerably larger than the external diameter of thecylindrical projection (the nut) but smaller than the externaldimensions of the holding element (flange of the nut), and an insulatordevice being arranged between the cage and the cylindrical projection.

Electrically insulating cage nuts of this type are preferably used wherethe internal thread of a nut fastened to a component is to be preventedfrom being clogged with the coating material or finish duringelectrostatic coating (that is to say, for example, duringelectrophoresis coating) of the component.

PRIOR ART

In accordance with the prior art according to DE 94 09 087 U1 and DE 19533 138 C1, which is hitherto standard in the industry, electricallyinsulated cage nuts of this type comprise a two-part insulator elementwhich push into the opening in the cage from outside and are retainedthere by an insulating shim fastened to the cylindrical projection ofthe nut body.

This prior art provides a complex and laborious production method, sinceat least four individual components are always required, and in additionthe construction is not very reliable in all installation positions(overhead, suspended laterally when passing through the immersioncoating bath) and not very resistant.

DESCRIPTION OF THE INVENTION

The object of the invention is therefore to develop an electricallyinsulating cage nut of this type in such a way that manufacturingbecomes significantly simpler and more cost-effective, and at the sametime the stability and reliability is considerably improved in allinstallation positions of the cage nut.

This object is achieved according to the invention in that the insulatordevice is formed in one piece, and therefore only three components arerequired.

It is particularly preferred for the insulator device to comprise ahollow cylindrical body, by means of which said device is rigidlyattached to the cylindrical projection and said body comprisesinsulating plates extending outwards in a planar manner at the two endsof said body, between which plates the edge of the opening is movablyreceived in the cage at least radially relative to the axis of rotationof the cylindrical projection.

It is particularly preferred for the insulating plate arranged on theholding element to cover the entire holding element towards the cage. Inorder to achieve protection against torsion and the insulating effect bymeans of as few components as possible, it is preferred for theinsulating plate arranged on the holding element to be in the shape ofan elongate rectangle and to comprise two longer sides opposite oneanother. It is particularly preferred for the insulating plate facingaway from the holding element to be in the shape of a rounded, laterallycurved rectangle. The cage nut according to the invention can beparticularly simply and cost-effectively produced by the insulatordevice being inserted laterally into the cage and the nut body beingpushed or pressed into the insulator device in the axial direction andbeing caulked there.

In the following, the present invention will be described in greaterdetail with reference to the embodiment shown in the appended drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is an axial cross-section of a cage nut according to theinvention;

FIG. 2 shows the cage nut according to the invention, viewed from thescrew-in side;

FIGS. 3 to 6 are various spatial views of the cage nut according to theinvention.

PREFERRED EMBODIMENT OF THE INVENTION

FIG. 1 shows a cage nut according to the invention which has been cutalong the screw-in axis.

The cage nut 10 shown according to the invention comprises a nut body 12which is received in a cage 14. The nut body 12 comprises a cylindricalprojection 16 and a widened holding element 18. The cylindricalprojection 16 has a coaxial internal thread 20 and extends outwardsthrough an opening 22 in the cage 14.

The internal diameter of the opening 22 is considerably larger than theexternal diameter of the cylindrical projection 16, but smaller than theexternal dimensions of the holding element 18.

Here, the opening 22 is open towards one side in order to make it easierto mount the nut body 12 in the cage 14.

According to the invention, an insulator device 24 which is formed inone piece is arranged between the cage 14 and the cylindrical projection16. The insulator device 24 comprises a hollow cylindrical body 26, bymeans of which said device is rigidly attached to the cylindricalprojection 16. In this case, the insulator device 24 can be attached tothe cylindrical projection 16 of the nut body 12 by interference fit, bybonding or, as can be seen here with reference to the caulk channels 28,by caulking. The caulking between the cylindrical projection 16 of thenut body 12 and the insulator device 24 is preferably carried out atthree points each spaced apart by 120°, or four points (not shown) eachspaced apart by 90°. As a result, the nut is located in the cage 14 andthe insulator device 24 in such a way that it cannot be lost. The hollowcylindrical body 26 of the insulator device 24 comprises insulatingplates 30, 32 extending outwards in a planar manner at the two ends ofsaid body. Said two insulator plates 30 and 32 are attached to thehollow cylindrical body 26 at a distance from one another in the axialdirection in such a way that the cage 14 can move slightly (not in aclamping manner) between the two insulator plates 30, 32. Four raisedpoints (not shown) are attached to the insulator plates 30, 32 in such away that the insulator plates do not contact the cage 14 over the entiresurface thereof, but only at tangential points. Bonding by adhesive andcohesive forces of the coatings is thus prevented. The edge 34 of theopening 22 is received between said insulator plates 30, 32 in the cage14 in such a way that it is movable at least radially relative to theaxis of rotation of the cylindrical projection 16.

The insulating plate 30 facing away from the holding element 18 is inthe shape of a rounded, laterally curved rectangle, while the shape ofthe insulating plate 32 arranged on the holding element covers theentire holding element 18 towards the cage 14 with a slight protrusion,in such a way that the nut body 12 does not directly touch the cage 14,whether it is in a horizontal, overhead or lateral position, andtherefore insulates the nut body. Therefore, there cannot be anelectrical flux.

The holding element 18 is in the shape of a thick, cylindrical circulardisc of which two opposite sides are cut off.

By means of the present invention, manufacturing an electricallyinsulated cage nut is made considerably simpler, the mechanicalresistance being considerably improved and improved insulation beingensured between the nut body and the cage at the same time.

1. Electrically insulating cage nut (10) comprising a nut body (12)which is contained in a cage (14), in which the nut body (12) comprisesa cylindrical projection (16) and a widened holding element (18), andthe cylindrical projection (16) has an internal thread (20) and extendsoutwards through an opening (22) in the cage (14), the internal diameterof the opening (22) being considerably larger than the external diameterof the cylindrical projection (16), but smaller than the externaldimensions of the holding element (18), and an insulator device (24)being arranged between the cage (14) and the cylindrical projection(16), characterised in that the insulator device (24) is formed in onepiece and therefore the cage nut (10) only consists of three components(12, 14, 24).
 2. Electrically insulating cage nut (10) according toclaim 1, characterised in that the insulator device (24) comprises ahollow cylindrical body (26), by means of which said device is rigidlyattached to the cylindrical projection (16) and said body comprisesinsulating plates (30, 32) extending outwards in a planar manner at thetwo ends of said body, between which plates the edge (34) of the opening(22) is movably received in the cage (14) at least radially relative tothe axis of rotation of the cylindrical projection (16).
 3. Electricallyinsulating cage nut (10) according to claim 2, characterised in that theinsulating plate (32) arranged on the holding element (18) covers theentire holding element (18) towards the cage (14) with a slightprotrusion, in such a way that the nut body does not touch the cage,whether it is in a horizontal, overhead or lateral position. 4.Electrically insulating cage nut (10) according to claim 3,characterised in that the insulating plate (32) arranged on the holdingelement (18) is in the shape of an elongate rectangle and comprises twolonger sides opposite one another.
 5. Electrically insulating cage nut(10) according to claim 2, characterised in that the insulating plate(30) facing away from the holding element (18) is in the shape of arounded, laterally curved rectangle.
 6. (canceled)
 7. A method forproducing a cage nut, said method comprising the following steps:inserting an insulator device being formed of one piece laterally into acage having an opening therethrough, the opening having an internaldiameter substantially larger than an external diameter of a cylindricalprojection of a nut body and substantially smaller than externaldimesions of a nut body holding element; pushing or pressing the nutbody, having a cylindrical projection having an internal thread and awidened holding element, into the insulator device in an axialdirection; and caulking between the nut body and the insulator device.8. The method for producing a cage nut according to claim 7 wherein theinsulator device comprises a hollow cylindrical body for rigidlyattaching the insulator device to the cylindrical projection of the nutbody, and the hollow cylindrical body comprises insulating platesextending outwards in a planar manner at two ends of the hollowcylindrical body, between the insulating plates an edge of an opening ismovably received in the cage at least radially relative to an axis ofrotation of the cylindrical projection.
 9. The method for producing acage nut according to claim 8 wherein one of the insulating plates beingarranged on a holding element covers the entire holding element towardsthe cage with a slight protrusion, such that the nut body does not touchthe cage, whether being in a horizontal, overhead or lateral position.10. The method for producing a cage nut according to claim 9 wherein theinsulating plate arranged on the holding element is in the shape of anelongated rectangle and comprises two longer sides opposite one another.11. The method for producing a cage nut according to claim 8 wherein oneinsulating plate faces away from the holding element and is in the shapeof a rounded, laterally curved rectangle.